John m



( No Model.)

M HARTMAN- METHOD 0F PREVENTING GHILLING OF BLAST PURNAGES.

No.1292-,305- Patented Jan. 22, 1884.

Siggi-ATT? t 'gf' aan? "L Q? m2? Wi'nesses Fv/ i lUivirnn Srarns PATENT -irricin J O15-IN M. HARTMAN, OF PHILADELPHIA, PENNSYLVANIA.-

"lVl ETHOD OF 4PR srncrricn'rronforming part of Letters' Patent No. 292,305, dated January 2e, rasa. nppnanon nieu october i7, ists. (No proud.)

To all whom t may concern: i

Beit known that I, JOHN M. Han/rims, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Method of Preventing the Chilling of Blast-Furnaces through the Accumulation'of Cinder in the Vicinity of the Tuyeres.

The following is a specification of my invention, the accompanying drawing serving to illustrate the nature of the difficulty to be remedied and the mode of operation which I pursue in order -to obviate it.

It is Well known that one of the most usual and most troublesome causes of chilling in furnaces is the accumulation of cinder opposite to the tuyercs. AIVlien a furnace is working properly, the contents of the interior at this point and for some distance above are entirely composed of the burning coal or other fuel-a condition of affairs which not only effects the reduction of the ore above, tains the iron and cinder in the crucible below the tuyeres at the proper melting temperature. If, by inattention, the cinder is permitted to accumulate until it reaches the tuyeres, a chilling at once takes place in front of the tuyere, as the temperature of the entering blast is not usually over 12000, while the melting-point of the cinder is about 35000. This chilling of the einder soon formsa shell or coating opposite to the tuyercs impervious to the blast, so that the latter is prevented from reaching the coals and maintaining the combustion at the tuyeres. The blast then tends to force vits way up the side of the furnace, andthe chilling of the cinder maycontinue upward until a shell or roof thereof is formed above the tuyere and the latter becomes entirely inefficient for supplying air. Moreover, the tending of this direction of the blastis to burn away the wall above the tuyere and endanger the furnace. It is not practicable to break or pierce this shell of hardened cinder by means of bars or tools, as the heat is sufficient to soften them, and they bend up when applied, so that the furnace fre quently remains for days or Weeks in an impaired condition, until, by forcing or otherwise manipulating the blast and using a large amount. of extra coal, the cinder has become melted and worked away from the tuyeres.

but maindown and apertures dug into thebottom for the removal of the cinder bodily, and such eX- cavation has been aided by blasting with eX- plosives, but of course with the attendantloss of time from the stopping of the furnace, and with the further disadvantage that the chilling continues in a constantly-increasin g ratio `from the air-supply being cut off. v

I have discovered that by the use of a small torpedo or other explosive inserted through and fired in the immediate vicinity of the tuyere, cracks or orices can be readily made in the cinder shell, through which the air-blast can penetrate, such operation being conducted without stopping the furnace. rlhe torpedo should of course be applied as soon as the pres; ence of the cinder at the point becomes mani fest, this fact being readily determinable by examination through the tuyere. This method of opening air-passages into the interiorot' the furnace has the further advantage that, instead of further cooling the furnace, (as the opening or excavation to remove the cinder necessarily does,) it starts combustion and generates heat just at the point where an increase is needed.

In the accompanying drawing Iliave illusfurnace, the mode of operation above specified for my invention. The furnace shown contains features of construction which will form the subject of a separate application, and which consequently are not described herein.

A is the wall of the furnace; B, the tuyere, and C the stock within the furnace.

D represents a shell or ledge of chilled cinder in the form and position frequently found to exist, and extending for some distance up- Ward from the tuyere-oriiice. Under these conditions the tendency of the blast is to work up between this cinder shell and the Wall'of the furnace, leaving a central core of stock.

The torpedo E should be inserted through the tuyere B, preferably by means of a heavy bar, F, which acts in measure as a tamping, and the torpedo, being forced into the cinder shell at a point opposite to the tuyere, is then exploded. The result of the explosion is to open fissures .or cracks in the shell, allowing the `blast to pass through the shell into the intrated, by a view in vertical section through al In some instances furnaces have been shut A IOO terior of the furnace, re-establishing,` the combustion at the tuyeres and soon melting the remaining portions of the einder.

I prefer to construct the torpedo of a stout Wooden case or shell holding a sufcient quantity of giant-powder or other explosive, and having a proper fuse attachment for firing. The amount of explosive required will of course Vary with the extent and thickness of the einder shell formed; but ordinarily, if the operation is timely, a very small eharge-say ftwo ounces-of giant-powder Will suffice, since the object is not to blast out or remove'the einder, but merely to open cracks therein and permit the entrance of the air-blast.

v I claim-- v The hereinbefore-deseribecl method of pref venting the chilling of blasturnaees through the formation of einder shells, and of restoring the blast-circulation therein by exploding a torpedo at a point opposite to the tuyere and in juxtaposition to the einder shell, and immediately forcing the blast through the fissures formed by such explosion.

' JOHN M.' HARTMAN. Titnessesz I J; WALTER DoUGLAss, JAMES C. LYNN. 

